// Copyright (c) 2019-present, iQIYI, Inc. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//

// Created by caikelun on 2019-09-25.
package xcrash;

import android.app.Activity;
import android.app.Application;
import android.os.Bundle;
import java.util.LinkedList;

class ActivityMonitor {

  private static final ActivityMonitor instance = new ActivityMonitor();

  private LinkedList<Activity> activities = null;
  private boolean isAppForeground = false;

  private static final int MAX_ACTIVITY_NUM = 100;

  private ActivityMonitor() {}

  static ActivityMonitor getInstance() {
    return instance;
  }

  void initialize(Application application) {
    activities = new LinkedList<Activity>();

    application.registerActivityLifecycleCallbacks(
        new Application.ActivityLifecycleCallbacks() {

          private int activityReferences = 0;
          private boolean isActivityChangingConfigurations = false;

          @Override
          public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
            activities.addFirst(activity);
            if (activities.size() > MAX_ACTIVITY_NUM) {
              activities.removeLast();
            }
          }

          @Override
          public void onActivityStarted(Activity activity) {
            if (++activityReferences == 1 && !isActivityChangingConfigurations) {
              isAppForeground = true;
            }
          }

          @Override
          public void onActivityResumed(Activity activity) {}

          @Override
          public void onActivityPaused(Activity activity) {}

          @Override
          public void onActivityStopped(Activity activity) {
            isActivityChangingConfigurations = activity.isChangingConfigurations();
            if (--activityReferences == 0 && !isActivityChangingConfigurations) {
              isAppForeground = false;
            }
          }

          @Override
          public void onActivitySaveInstanceState(Activity activity, Bundle outState) {}

          @Override
          public void onActivityDestroyed(Activity activity) {
            activities.remove(activity);
          }
        });
  }

  void finishAllActivities() {
    if (activities != null) {
      for (Activity activity : activities) {
        activity.finish();
      }
      activities.clear();
    }
  }

  boolean isApplicationForeground() {
    return this.isAppForeground;
  }
}
